# Copyright 2012 SINA Corporation
# Copyright 2014 Cisco Systems, Inc.
# All Rights Reserved.
#
#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#
#         http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.
#

"""Extracts OpenStack config option info from module(s)."""

from __future__ import print_function

import argparse
import imp
import os
import re
import socket
import sys
import textwrap

from oslo.config import cfg
import six
import stevedore.named

from nova.openstack.common import gettextutils
from nova.openstack.common import importutils

gettextutils.install('nova')

STROPT = "StrOpt"
BOOLOPT = "BoolOpt"
INTOPT = "IntOpt"
FLOATOPT = "FloatOpt"
LISTOPT = "ListOpt"
DICTOPT = "DictOpt"
MULTISTROPT = "MultiStrOpt"

OPT_TYPES = {
    STROPT: 'string value',
    BOOLOPT: 'boolean value',
    INTOPT: 'integer value',
    FLOATOPT: 'floating point value',
    LISTOPT: 'list value',
    DICTOPT: 'dict value',
    MULTISTROPT: 'multi valued',
}

OPTION_REGEX = re.compile(r"(%s)" % "|".join([STROPT, BOOLOPT, INTOPT,
                                              FLOATOPT, LISTOPT, DICTOPT,
                                              MULTISTROPT]))

PY_EXT = ".py"
BASEDIR = os.path.abspath(os.path.join(os.path.dirname(__file__),
                                       "../../../../"))
WORDWRAP_WIDTH = 60


def raise_extension_exception(extmanager, ep, err):
    raise


def generate(argv):
    parser = argparse.ArgumentParser(
        description='generate sample configuration file',
    )
    parser.add_argument('-m', dest='modules', action='append')
    parser.add_argument('-l', dest='libraries', action='append')
    parser.add_argument('srcfiles', nargs='*')
    parsed_args = parser.parse_args(argv)

    mods_by_pkg = dict()
    for filepath in parsed_args.srcfiles:
        pkg_name = filepath.split(os.sep)[1]
        mod_str = '.'.join(['.'.join(filepath.split(os.sep)[:-1]),
                            os.path.basename(filepath).split('.')[0]])
        mods_by_pkg.setdefault(pkg_name, list()).append(mod_str)
    # NOTE(lzyeval): place top level modules before packages
    pkg_names = sorted(pkg for pkg in mods_by_pkg if pkg.endswith(PY_EXT))
    ext_names = sorted(pkg for pkg in mods_by_pkg if pkg not in pkg_names)
    pkg_names.extend(ext_names)

    # opts_by_group is a mapping of group name to an options list
    # The options list is a list of (module, options) tuples
    opts_by_group = {'DEFAULT': []}

    if parsed_args.modules:
        for module_name in parsed_args.modules:
            module = _import_module(module_name)
            if module:
                for group, opts in _list_opts(module):
                    opts_by_group.setdefault(group, []).append((module_name,
                                                                opts))

    # Look for entry points defined in libraries (or applications) for
    # option discovery, and include their return values in the output.
    #
    # Each entry point should be a function returning an iterable
    # of pairs with the group name (or None for the default group)
    # and the list of Opt instances for that group.
    if parsed_args.libraries:
        loader = stevedore.named.NamedExtensionManager(
            'oslo.config.opts',
            names=list(set(parsed_args.libraries)),
            invoke_on_load=False,
            on_load_failure_callback=raise_extension_exception
        )
        for ext in loader:
            for group, opts in ext.plugin():
                opt_list = opts_by_group.setdefault(group or 'DEFAULT', [])
                opt_list.append((ext.name, opts))

    for pkg_name in pkg_names:
        mods = mods_by_pkg.get(pkg_name)
        mods.sort()
        for mod_str in mods:
            if mod_str.endswith('.__init__'):
                mod_str = mod_str[:mod_str.rfind(".")]

            mod_obj = _import_module(mod_str)
            if not mod_obj:
                raise RuntimeError("Unable to import module %s" % mod_str)

            for group, opts in _list_opts(mod_obj):
                opts_by_group.setdefault(group, []).append((mod_str, opts))

    print_group_opts('DEFAULT', opts_by_group.pop('DEFAULT', []))
    for group in sorted(opts_by_group.keys()):
        print_group_opts(group, opts_by_group[group])


def _import_module(mod_str):
    try:
        if mod_str.startswith('bin.'):
            imp.load_source(mod_str[4:], os.path.join('bin', mod_str[4:]))
            return sys.modules[mod_str[4:]]
        else:
            return importutils.import_module(mod_str)
    except Exception as e:
        sys.stderr.write("Error importing module %s: %s\n" % (mod_str, str(e)))
        return None


def _is_in_group(opt, group):
    "Check if opt is in group."
    for value in group._opts.values():
        # NOTE(llu): Temporary workaround for bug #1262148, wait until
        # newly released oslo.config support '==' operator.
        if not(value['opt'] != opt):
            return True
    return False


def _guess_groups(opt, mod_obj):
    # is it in the DEFAULT group?
    if _is_in_group(opt, cfg.CONF):
        return 'DEFAULT'

    # what other groups is it in?
    for value in cfg.CONF.values():
        if isinstance(value, cfg.CONF.GroupAttr):
            if _is_in_group(opt, value._group):
                return value._group.name

    raise RuntimeError(
        "Unable to find group for option %s, "
        "maybe it's defined twice in the same group?"
        % opt.name
    )


def _list_opts(obj):
    def is_opt(o):
        return (isinstance(o, cfg.Opt) and
                not isinstance(o, cfg.SubCommandOpt))

    opts = list()
    for attr_str in dir(obj):
        attr_obj = getattr(obj, attr_str)
        if is_opt(attr_obj):
            opts.append(attr_obj)
        elif (isinstance(attr_obj, list) and
              all(map(lambda x: is_opt(x), attr_obj))):
            opts.extend(attr_obj)

    ret = {}
    for opt in opts:
        ret.setdefault(_guess_groups(opt, obj), []).append(opt)
    return ret.items()


def print_group_opts(group, opts_by_module):
    print("[%s]" % group)
    print('')
    for mod, opts in opts_by_module:
        print('#')
        print('# Options defined in %s' % mod)
        print('#')
        print('')
        for opt in opts:
            _print_opt(opt)
        print('')


def _get_my_ip():
    try:
        csock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        csock.connect(('8.8.8.8', 80))
        (addr, port) = csock.getsockname()
        csock.close()
        return addr
    except socket.error:
        return None


def _sanitize_default(name, value):
    """Set up a reasonably sensible default for pybasedir, my_ip and host."""
    if value.startswith(sys.prefix):
        # NOTE(jd) Don't use os.path.join, because it is likely to think the
        # second part is an absolute pathname and therefore drop the first
        # part.
        value = os.path.normpath("/usr/" + value[len(sys.prefix):])
    elif value.startswith(BASEDIR):
        return value.replace(BASEDIR, '/usr/lib/python/site-packages')
    elif BASEDIR in value:
        return value.replace(BASEDIR, '')
    elif value == _get_my_ip():
        return '10.0.0.1'
    elif value in (socket.gethostname(), socket.getfqdn()) and 'host' in name:
        return 'nova'
    elif value.strip() != value:
        return '"%s"' % value
    return value


def _print_opt(opt):
    opt_name, opt_default, opt_help = opt.dest, opt.default, opt.help
    if not opt_help:
        sys.stderr.write('WARNING: "%s" is missing help string.\n' % opt_name)
        opt_help = ""
    opt_type = None
    try:
        opt_type = OPTION_REGEX.search(str(type(opt))).group(0)
    except (ValueError, AttributeError) as err:
        sys.stderr.write("%s\n" % str(err))
        sys.exit(1)
    opt_help = u'%s (%s)' % (opt_help,
                             OPT_TYPES[opt_type])
    print('#', "\n# ".join(textwrap.wrap(opt_help, WORDWRAP_WIDTH)))
    if opt.deprecated_opts:
        for deprecated_opt in opt.deprecated_opts:
            if deprecated_opt.name:
                deprecated_group = (deprecated_opt.group if
                                    deprecated_opt.group else "DEFAULT")
                print('# Deprecated group/name - [%s]/%s' %
                      (deprecated_group,
                       deprecated_opt.name))
    try:
        if opt_default is None:
            print('#%s=<None>' % opt_name)
        elif opt_type == STROPT:
            assert(isinstance(opt_default, six.string_types))
            print('#%s=%s' % (opt_name, _sanitize_default(opt_name,
                                                          opt_default)))
        elif opt_type == BOOLOPT:
            assert(isinstance(opt_default, bool))
            print('#%s=%s' % (opt_name, str(opt_default).lower()))
        elif opt_type == INTOPT:
            assert(isinstance(opt_default, int) and
                   not isinstance(opt_default, bool))
            print('#%s=%s' % (opt_name, opt_default))
        elif opt_type == FLOATOPT:
            assert(isinstance(opt_default, float))
            print('#%s=%s' % (opt_name, opt_default))
        elif opt_type == LISTOPT:
            assert(isinstance(opt_default, list))
            print('#%s=%s' % (opt_name, ','.join(opt_default)))
        elif opt_type == DICTOPT:
            assert(isinstance(opt_default, dict))
            opt_default_strlist = [str(key) + ':' + str(value)
                                   for (key, value) in opt_default.items()]
            print('#%s=%s' % (opt_name, ','.join(opt_default_strlist)))
        elif opt_type == MULTISTROPT:
            assert(isinstance(opt_default, list))
            if not opt_default:
                opt_default = ['']
            for default in opt_default:
                print('#%s=%s' % (opt_name, default))
        print('')
    except Exception:
        sys.stderr.write('Error in option "%s"\n' % opt_name)
        sys.exit(1)


def main():
    generate(sys.argv[1:])

if __name__ == '__main__':
    main()
